Engine starter



Patented Jan. 2, 1945 v ENGINE STARTER g 3 John W. .Fitn Gerald,deceased, late of Milwaukee,

Wis, by Mary GqFitz Gerald,executrix, Milwauikee, Wis.,,' assignor. to;Briggs ;& Stratton Corporation, Milwaukeey Wis, a corporation of 3Delaware Application June 19, 1943, Serial No.:491,509 .01. 74

This invention relates to engine starters of 1 the so-called automatictype wherein the operation of the starter automatically propels thepinion into and out of mesh with the ring gear of the en ine.

In starters of this type it is essential that the drive transmission tothe pinion include a yieldablebryresilient elementandthis invention is"concerned primarilywith enginestarters ofthe' type wherein thisnecessary resiliency isafiorcltion of the shaft 1 and to be withdrawn edby a bod-yof' elastically deformablematerial such as rubber. l l

In" all engine starters of this general classthe anchorage of the pinionstop which defines the operative driving position of the pin-ion has presented dim'culties, especially in the smallelf start- C ers where spaceis at a premium and themotor shaft is small in diameter. l I

"It is therefore an object of this invention to provide a new andimproved manner of anchoring the pinion stop with a view towa1-dovercoming the dimculties heretofore encountered. To this end theinvention broadly contemplates a yieldable anchorage'for thepinion-stop.

More specifically it is an object of this invention to provide aresilient or yield'able anchoragefor the pinion stop so designed andconstructed' that the element which afi-ords 'the resiliency the drivingconnection betweenthe pinion actuator and drive shaft also provides theyield for the pinion stop. I

With the aboveand other objects in view,

which will appear as the description proceeds] this inventionresidesinthe novel construction,

combination and arrangement of parts substan tially ashereinafterdescribed, andrnore parunclerstood thatsuch changesin the preciseembodiment. of the hereind iscl'osed invention may be made as. comewithin the'scopeof the claims.

gear of an engine to be started, with whi'ch'a pinion 6 is adapted to bemeshed. vThepinion 6 is movable axially along and rotarily with amotordliven shaft 1 and is adapted' to beauto-t matically propelled intomeshupon initiai rotatron-r mesh when the engine starts.

Such longitudinal propulsion of the pinion is effected by therelative.rotation between it and an actuator 8. The actuator 8 consistsiofa-sleeve having external screw threads 9; and is mounted on a. hollowshaftor tube Ht loose on the. shaft 1. The pinion 6 is. carried by a;tubular sleeve, H

which has an internallythreaded nut member I2 fixedwtherein. The nutmember is threaded on i the actuator 8 and thereby supplies thescrewthreaded connection between theipinion audactuator'by which relativerotation of these parts effects the desired advance and; retraction ofthe pin on. The nut member alsov cooperates with a-flange l3 fixed tothe tubefllt to support the pinion and its sleeve for longitudinalmovement;

A resilient drive coupling indicated" generallyby the numeral HI.drivinglyconnects theactuator with the motor driven shaft! I couplingconsists of an. annulus 15 of rubber or any 1 other material havingcubical elasticityxconfinedl between a driving abutment. or flange l6and a. I

driven abutment or flange ll;

In the construction 1 illustrated, abutment i6 is fixed to the driveshaft 1 by a screw l8 and has a driving part t9 nonrotatably connectedtherewith; said d-rivingpart l9 being ireeto move axially with respecttothedrive shaft *ticularly definedby the appended claims, it being i Theaccompanying drawing illustrates one complete example. of the physicalembodiment of theinvention constructed according to the best. mode sofar devised for the practical application of the principles thereof, andwhich: Figure l is a view in side elevation withparts broken away and insection of a starter embodying this invention andshowing the pinion inits retracted position; and

Figure 2 is a view similar to Figure 1 but showing the pinion advancedto itsoperative driving position. I

Referring now more particularly to the accompanying drawing, in whichlike numerals indicatelike parts,-the numeral 5 designates a ringpression to provide, irictionaldriving'. engagement H to apply axialpressure on the annulus" l 5'when the pinion reaches its operativedriving position;

abutment IT is partofor fixedto the g The driven actuator.

A shell 20 fixed to the abutment or flange. [T

and engaging lover the abutment or flange [6- lirnits the extent towhich theabutments may, separate and also encloses the elastic airmulus-The axial dimension of the shell 2!] is such. that it maintains theannulus under slight precombetween it and the driving and drivenabutments or flanges.

When the pinion reaches its operative driving position its nut l2collides with the flange l3 1 carried by the tube It). The tube I0 thushas the impact of arresting the pinion advance transmit ted thereto. Afreely rotatable. connection with the drive part I9 provided by a flange2| on the" tube engaging behind the drive part restrains the the drivingpinion against creeping forward when the starter is idle.

From the foregoing description, taken in connection with theaccompanying drawing, it will be readily apparent to those skilled inthe art that this invention provides a starter of novel design andconstruction and that by virtue of the internal location andyieldability of its pin-v ion stop it is particularly well adapted forsmall starters.-

What is claimed as the invention is:

I 1.;Inan engine starter: a pinion movable to and from an operativedriving position; a pinion actuator connected with the pinion andoperable to actuate the pinion; a resilient drive for the pinionactuator including an elastically deformable member; a pinion stop atone side of and spaced from the elastically deformable member forlimiting movement of the pinion to its operative position; and meansextending from the pinion stop through and beyond said elasticallydeformable member to apply the pinion thrust on the-stop to theelastically deformable member so that the pinion stop yields-slightly asit arrests the advance of the pinion.

2. In an engine starter: a drive shaft; a pinion movable along thedriveshaft to and from an operative driving position; a pinion actuatorconnected with the pinion and operable upon relative rotationtherebetween to propel the pinion toward and from its operative drivingposition; means connecting the actuator with the drive shaft'to hold thesame against endwise movement in one direction while permitting freerotation of the actuator about the drive shaft; a resilient torquetransmittingconnection between the drive shaft and pinion actuatorincluding a member axially yieldable; a pinion stop for limitingmovement of the pinion as it reaches its operative driving position; andmeans for connecting the pinion stop to the drive shaft through saidaxially yieldable member and said connection'between the pinion actuatorand the drive shaft whereby pinion thrust against the stop is cushioned,

3. In'an engine starter having a pinion and having a resilient torquetransmitting connedtion through which torque is transmitted to thepinion and which includes an elastically deform-.

deformable annulus so as to restrain the stop against axial movement inthe direction of pinion movement toward its operative driving positionthrough said elastically deformable annulus whereby pinion thrust onsaid stop is translated into axial compression of said elasticallydeformable annulus.

4. In an engine starter: a drive shaft; a pinion movable along the shaftto and from an operative driving position; a pinion actuator operativelyconnected with the pinion and operative upon relative rotationtherebetween to move the pinion longitudinally to and from its operativedriving position; a resilient torque transmitting connection between thepinion actuator and the drivin shaft comprising, a driven part on theactuator, a driving part nonrotatably and axially connected with thedrive shaft, and an elastically deformable member between said drivingand driven parts; means connecting the driven part with the drive shaft;means supporting the driven part from the drive shaft so as to maintainthe elastically deformable member under a degree of precompression, saidsupport leaving the pinion actuator free to revolve with respect to thedrive shaft; a pinion stop for limiting movement of the pinion towardits operative driving position; and tension means connecting the pinionstop with the driving part so that the pinion stop is connected to thedrive shaft through the elastically deformable member.

5. In an engine starter: a drive shaft; a pinion movable along-the driveshaft; a barrel connected with the pinion; a nut in the barrel; a hollowscrew-threaded pinion actuator threaded in said nut; a'tube loose on thedrive shaft and inside of and passing through the hollow screwthreadedpinion actuator; a stop fixed on 'the tube inside the barrel to beengaged 'by'the nut when the pinion reaches its operative drivingposition; and a resilient torque transmitting cou pling for driving thepinion actuator from the drive shaft having a connection with said tubeby which the thrust of the pinion nut on the stop is cushioned.

6. In an engine starter: a drive shaft; a pini-on movable along thedrive shaft; a barrel connected with the pinion; a nut in the barrel; a

hollow screw-threaded pinion actuator threaded and driven parts engagingopposite sides of an elastically deformable member, the driving partbeing free to move axially with respect to-the drive shaft; and a freelyrotatable connection between the tube and said drive part whereby thetube and pinion stop receives support through the elastically deformablemember. i

g I MARY- o. FITZ. GERALD,=, Exeeutria: of the Estate of John- FitzGerald,

, Deceased.

